Elevator systems of conventional type generally have a drive, a drive control that is assigned to the drive, and a brake system. Gradually, existing elevator systems are being modernized, to improve their energy efficiency, increase their safety, and fulfill the latest conditions for authorization of operation.
In the case of modernization, particularly the safety aspect is given great emphasis, and often the drive machine and/or the drive control are replaced. As a new drive control it is usual to employ a VVVF (variable voltage, variable frequency) control or an ACVF (alternating current, variable frequency) control. As a new drive machine, a Schindler SGB 142 drive machine can be advantageously employed. In this Schindler SGB 142 drive machine, the holding brake fulfills the stipulations of the safety regulations, and an additional rope brake or safety gear is no longer required. The condition, however, is that the holding brake of the newly installed drive machine is correspondingly monitored.
Also in the case of new elevator systems, there is a need for better monitoring of the brake systems.
If the holding brakes do not release correctly when the drive machine starts, they can become worn. Moreover, unreleased brakes can generate smoke, which under certain circumstances can cause a hazard to the passengers. The generation of smoke can arise because the drive machine often develops sufficient drive torque to assure travel operations also with unreleased brakes.
An exemplary device for monitoring an elevator control is to be found in patent specification EP 903 314 B1.
The task therefore presents itself of proposing a corresponding monitoring solution for elevator systems, e.g. for modernized elevator systems with a newly installed drive machine, which allows monitoring of the holding brake.
Since, however, existing elevator systems can also be modernized in that the holding brake is monitored by a drive machine that is present, it is also to be considered as a task of the present invention to develop a monitoring solution for such situations. The monitoring solution that is sought should generally be usable also for new elevator systems.
Preferably, the monitoring solution should therefore be universally usable and flexibly designed, so as to be able to employ one and the same monitoring solution in the most diverse elevator systems. Preferably, the monitoring solution should be so designed that, with only a few manual adjustments and/or reprogrammings, an adaptation to the respectively prevailing situation can be undertaken.